Propane is used in the field of semiconductor electronic materials, such as materials for SiC which is a next generation power device material, and is used in hydrogen diluted propane gas and propane pure gas. For such application, propane is required to have higher purity.
In a raw material gas containing propane as a main component used as a raw material of high purity propane, for example, ethane, propylene, isobutane and normal butane are contained at high concentration as impurities. Examples of a method of purifying propane from the raw material gas include methods such as distillation, membrane separation, adsorption separation, absorption separation and the like.
Patent Literature 1 describes a method of separating propylene and propane by a distillation method. For example, in the case of separating propylene and propane by the distillation method as in the technique described in Patent Literature 1, since boiling points thereof are close to each other (boiling point difference is 4.9° C.), it is required to repeat the distillation in multiple stages for separation thereof. Accordingly, it is required to set up large-scale equipment and precise distillation conditions, which is a huge barrier to putting the equipment into practical use.
Patent Literature 1 describes a method of adsorbing and separating isobutane and normal butane, and propane using activated carbon and adsorbing and separating ethane and propylene, and propane using molecular sieve activated carbon. In the technique described in Patent Literature 2, although propane of high purity can be obtained without performing complicated operations such as distillation, when isobutane and normal butane and propane are adsorbed and separated using the activated carbon, there is a problem that the amount of propane adsorbed on the activated carbon is large and the yield of propane is poor.
As a method for solving such a problem, Patent Literature 3 describes a method of generating propane by bringing propylene and hydrogen into contact with each other to perform a hydrogenation reaction.